From 67e97a0fd3cb5e32b0062365007a6264a113da47 Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sun, 4 Oct 2020 20:04:11 +0100
Subject: [PATCH] into and from limb

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---
 src/bigfloat.rs | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/src/bigfloat.rs b/src/bigfloat.rs
index 9a6032db..aa7bca34 100644
--- a/src/bigfloat.rs
+++ b/src/bigfloat.rs
@@ -122,6 +122,23 @@ mod innards {
   }
 
 }
+
+impl From<u64> for Limb {
+  fn from(u: u64) -> Limb {
+    assert_eq!(0, u >> 48);
+    Limb([ ((u >> 32) & 0xffff) as u16,
+           ((u >> 16) & 0xffff) as u16,
+           ((u >>  0) & 0xffff) as u16 ])
+  }
+}
+impl From<Limb> for u64 {
+  fn from(l: Limb) -> u64 {
+    ((l.0[0] as u64) << 32) |
+    ((l.0[1] as u64) << 16) |
+    ((l.0[2] as u64) <<  0)
+  }
+}
+
 /*/
 impl Bigfloat {
   fn from_parts(sign: Sign, exp: Sz, limbs: &[Limb]) {
-- 
2.30.2